Explanation: Neutrinos,
along with
things like electrons and quarks, are fundamental pieces of
matter according to
physicists' Standard Model.
But neutrinos are hard to detect.
Readily produced
in nuclear reactions and
particle collisions, they can easily pass completely through planet
Earth without once interacting with any other particle.
Constructed in an unused mine in Japan,
an ambitious large-scale experiment
designed to detect and study neutrinos is known
as Super-Kamiokande or "Super-K".
Only(!) 500 days worth of data was needed to produce
this "neutrino image" of the Sun,
using Super-K
to detect the neutrinos from nuclear fusion
in the solar interior.
Centered on the Sun's postion, the picture covers a significant
fraction of the sky (90x90 degrees in R.A. and Dec.).
Brighter colors represent a larger flux of neutrinos.